1. Field of the Invention
The present invention relates to a cosmetic agent containing (A) a particular cysteine derivative or a salt thereof and (B) a particular whitening agent.
2. Discussion of the Background
Conventionally, to prevent suntan, pigmented spot, freckle of the skin and maintain the inherent fair skin, whitening cosmetic agents containing various whitening agents such as kojic acid, arbutin, rcinol, ellagic acid and the like have been proposed. However, when these substances are blended in large amounts, problems in the sense of use and safety may occur, which prevents use thereof at a concentration expected to provide a sufficient effect.
On the other hand, patent document 1 describes that a cysteine derivative obtained by esterification of L-2-methylthiazolidine-2,4-dicarboxylic acid or a salt thereof is useful as a whitening agent etc. Furthermore, patent document 2 describes that 2-methylthiazolidine-2,4-dicarboxylic acid or a derivative thereof has a whitening action. However, since these derivatives are easily decomposed and insufficient in the stability, practicalization thereof has not been achieved. The particular cysteine derivative of the present invention is not described.